This invention is generally directed to charge transporting molecules, and more specifically the present invention is directed to imaging members having incorporated therein as charge transporting layers certain derivatives of arylamines. Thus, in one embodiment the present invention envisions layered photoresponsive imaging members comprised of a photogenerating layer and a charge transport layer having incorporated therein alkoxy derivatives of the tetraphenyl biphenyl diamines described in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference. Layered imaging members with the aforementioned alkoxy diamine transport molecules are useful in electrostatographic imaging systems, particularly xerographic imaging processes. Furthermore, the alkoxy derivatives of the tetraphenyl biphenyl diamines have desirable improved properties with regard to the parent tetraphenyl diamines inclusive of higher charge carrier mobilities, and increased solubility in inactive resinous binders.
Layered imaging members with charge transport molecules are disclosed in a number of prior art references inclusive of U.S. Pat. No. 4,265,990. These imaging members are generally comprised of supporting substrates, a photoconductive layer containing photogenerating pigments therein, and as a charge transport layer arylamines inclusive of alkyl, chloro substituted biphenyl, and chloro substituted tetraphenyl diamine transport molecules. One specific charge transport molecule disclosed in the prior art is N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[4,4'-biphenyl]-1,1'-diamine. The charge transport molecules of the present invention which are derivatives of the aforementioned arylamines exhibit higher charge carrier mobilities and increased solubility in resin binders. Increased carrier movement enables a desirable reduction in the concentration or amount of alkoxy amine transport molecule while simultaneously maintaining the high mobilities thereof required in the imaging member selected. Additionally, the use of decreased amounts of alkoxy transport molecule provides for an improvement in the mechanical characteristics of the resulting transport layers. These characteristics and other properties associated with the alkoxy arylamine transport molecules of the present invention permit the use of a number of different resinous binders, and allow the resulting imaging member to be useful for numerous imaging cycles at high process speeds; and wherein there is maintained high charge mobility in the charge transporting layers.
Also known are layered imaging members with polysilylene hole transporting molecules, reference copending application U.S. Ser. No. 694,862, entitled Photoresponsive Imaging Members with Polysilylenes Hole Transporting Compositions, the disclosure of which is totally incorporated herein by reference.
Many other patents disclose layered photoresponsive imaging members such as U.S. Pat. No. 3,041,167, which illustrates an overcoated member comprised of a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member can be utilized in an electrophotographic copying method by, for example, initially charging with an electrostatic charge of a first polarity, and imagewise exposing to form an electrostatic latent image which can be subsequently developed. Prior to each succeeding cycle, the imaging member can be charged with an electrostatic charge of a second polarity, which is opposite in polarity to the first polarity. Sufficient additional charges of the second polarity are applied creating across the member a net electrical field of the second polarity. Simultaneously, mobile charges of the first polarity are created in the photoconductive layer by applying an electrical potential to the conductive substrate. The imaging potential which is developed to form the visible imaging is present across the photoconductive layer and the overcoating layer.
Further, there is disclosed in Belgian Patent No. 763,540, an electrophotographic member having at least two electrically operative layers. The first layer is comprised of a photogenerating substance which injects carriers into a continuous active layer containing an organic transporting material which is substantially non-absorbing in the spectral region of intended use. Additionally, there is disclosed in U.S. Pat. No. 3,041,116, a photoconductive material containing a transparent plastic material overcoated on a layer of vitreous selenium contained on a substrate.
Furthermore, there is disclosed in U.S. Pat. Nos. 4,232,102 and 4,233,383, photoresponsive imaging members comprised of trigonal selenium doped with sodium carbonate, sodium selenite, and trigonal selenium doped with barium carbonate, and barium selenite or mixtures thereof. The disclosure of each of the aforementioned patents are totally incorporated herein by reference.
Additionally, the use of squaraine pigments in photoresponsive imaging members is known, reference U.S. Pat. No. 4,415,639 or other squaraine compositions, reference U.S. Pat. No. 4,471,041. The disclosure of each of the aforementioned patents are totally incorporated herein by reference. Also, as photogenerating pigments there can be selected metal phthalocyanines, metal free phthalocyanines, vanadyl phthalocyanines, selenium and selenium alloys; and perylene dyes, reference copending application U.S. Ser. No. 587,483, the disclosure of which is totally incorporated herein by reference.
While the above-described photoresponsive imaging members are suitable for their intended purposes, there continues to be a need for the development of improved members with new charge transporting molecules. Additionally, there continues to be a need for imaging members with charge transport molecules exhibiting desirable high charge carrier mobilities. Further, there is a need for imaging members with new charge transport molecules with increased solubility in resinous binder compositions. Furthermore, there continues to be a need for layered imaging members with charge transport molecules comprised of certain derivatives of tetraphenyl biphenyl diamines, and wherein the resulting members can be repeatedly used a number of imaging cycles without deterioration thereof from the machine environment or surrounding conditions. Moreover, there continues to be a need for improved layered imaging members wherein the material selected for the respective layers are substantially inert to users of such members. Also, there is a need for charge transporting layers wherein lower concentrations of the molecules present therein can be selected.